Can the Put rest api be configured to add new data as well as update existing data?

Summary:

Can the Put rest api be configured to add new data as well as update existing data

Content (required):

The put handler currently updates existing but fails to create any new data rows.

Can this be fixed in the handler sql below

Version (include the version you are using, if applicable):

Apex Cloud database

Code Snippet (add any code snippets that support your topic, if applicable):

BEGIN

UPDATE ADMIN.PUT SET (PROJECTID = :PROJECTID,PROJECTNAME = :PROJECTNAME,LOCATION = :LOCATION)

WHERE PROJECTID = :PROJECTID

END;